USB: option: Use generic USB wwan code

As this code was simply factored out of option, this is a simple
conversion.

Signed-off-by: Matthew Garrett <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Matthew Garrett

drivers/usb/serial/Kconfig

@@ -581,6 +581,7 @@ config USB_SERIAL_WWAN
 
 config USB_SERIAL_OPTION
 	tristate "USB driver for GSM and CDMA modems"
+	select USB_SERIAL_WWAN
 	help
 	  Say Y here if you have a GSM or CDMA modem that's connected to USB.